Modern digital printing systems are complex instruments with many moving parts. Over time, the print quality from such printing systems typically degrades due to a variety of factors including contamination on rollers, degradation of the roller materials, and loss of uniformity in recycled xerographic toner among possible factors. Traditional printer diagnostic mechanisms rely on examining the printed page output for print quality changes or relying on complex sensors within the printer mechanism. Each of these methods has its drawbacks.
Complex sensors embedded within the printer mechanism typically cannot monitor the entire paper path through the printer. Thus when failures occur in an area devoid of sensors, an educated guess needs to be made with respect to the cause of the problem. The number printer failures in areas devoid of sensors can be reduced by increasing the number of sensors in the system; however, increasing the number of complex sensors is expensive. Inferring the problem from the output of a printed page involves time, guesswork and typically skilled and thus expensive service personnel.
In either case, unless a sensor is located adjacent to the problem area, precise identification of the problem is difficult. If precise diagnosis of the cause of failure cannot be made, the typical solution is to replace key components until the problem is fixed. This process is inefficient and expensive.
Thus a method of diagnosing printing system status that is inexpensive and covers the entire paper path is needed.